1. The Field of the Invention
This application relates generally to noise-abatement devices. In particular, this application discusses noise-abatement devices for use with pneumatically operated tools, such as pneumatic percussive drills.
2. The Relevant Technology
The process of converting energy stored in compressed air into motion for powering a pneumatic tool generates a significant amount of noise as the spent air (exhaust) is exhausted. In particular, pneumatic tools are often operated by compressed air that is directed to a pneumatic cylinder. As compressed air expands in the cylinder, the air exerts pressure on an internal piston causing the piston to move from an initial position in a first direction for a determined distance. The travel of the piston within the pneumatic cylinder can be referred to as a stroke. As the piston nears the end of the stroke, the air in the cylinder is exhausted by way of an exhaust port. The piston is then returned to its initial position by an opposing force that is often provided by a spring and/or compressed air applied to the opposite side of the piston and the process begins again.
As spent compressed air is exhausted from the pneumatic cylinder, the spent compressed air expands rapidly causing a loud noise. Often, the operation of pneumatic tools requires a close proximity between the tool and an operator, and the noise generated by the tool can be loud enough to be potentially harmful to the operator. There are many approaches to reduce the noise from these devices. A common approach is a muffler consisting of an expansion chamber into which the exhaust flows and expands before venting to the atmosphere. Such designs take various geometric shapes including cylindrical, kidney-shaped, and rectangular. Another approach includes incorporating a series of internal chambers within an expansion chamber to allow the exhaust to progressively expand. While such approaches offer some improvement in noise reduction, given the close proximity of pneumatic tools and their operators, the noise reduction of current approaches is often insufficient to acceptably reduce the damaging and/or painful noise levels.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some examples described herein can be practiced